"Viewshed" is a recently coined term used to indicate the entire area an individual can see from a given point. Being able to determine the viewshed and how it could be altered is of particular use to park planners and landscape architects.

Viewsheds are characterized by establishing visibility between locations. Locations forming the viewshed of an area are connected by straight rays in three-dimensional space to the location of the 'viewer' or set of viewers.

Connectivity is precluded by topographic relief and surface objects forming ablsolute barriers. If more than one viewer is designated, individual locations within the viewshed may be assigned a value indicating the number or density of visual connections.